Field of the Invention
The invention relates generally to an optical lens system and, more particularly, to a zoom lens system having multiple lenses.
Description of the Related Art
Nowadays, a projection display device using a variable focus lens (zoom lens), which is capable of changing the size of an image projected onto a screen, has come into widespread use. Typically, the variable focus lens may include a large number of lenses to achieve high aberration correction, ensure telecentricity, and prevent a reduction in contrast or the occurrence of color unevenness. However, an increase in the number of lenses is accompanied by an increase in the fabrication costs. Therefore, it is desirable to provide a zoom lens system that has a reduced number of lenses and is favorable for improving imaging quality.